My life with progesterone

George Washington Corner (1889-1981) and Willard Myron Allen (1904-1993) (the latter a medical student at the time) first obtained a secretory endometrium in the rabbit uterus after injection of an extract of corpus luteum, which laid the groundwork for the isolation of progesterone. Illustrated above, several figures are from a nonpregnant rabbit uterus after an ophorectomy and various treatments: 1 and 5, Normal control from mature rabbit; 7, control from immature rabbit; 2, proliferative endometrium in response to 5 days treatment with corpus luteum extract; 3, same after a larger dose; 8, same in immature animal; 4, same after one-half minimal effective dose; 6, treatment with follicular fluid (presumably containing estrogen); 9, same in immature animal. These investigators also demonstrated that neither follicular fluid containing large amounts of estrogen nor placental extracts produced such a proliferative response. An important consequence of the discovery was that estrogen is required to prime the endometrium for the effect of progesterone. After this study, and continuing to work with George Corner, in the early to mid 1930s, Allen first isolated progesterone from the corpus luteum, purified it to homogenicity, demonstrated that it maintained pregnancy in various species, and gave it the name ‘‘progesterone.’’ In 1941, Allen joined the faculty of Washington University, St. Louis, as Professor and Head of the Department of Obstetrics and Gynecology, a position he held for 30 years. In 1971, he joined the faculty of the University of Maryland, Baltimore, and for over a decade continued to be active in the specialty.